KR20110015656A - Cylindrical battery - Google Patents

Abstract

The opening of the bottomed cylindrical battery case 1 is sealed by the assembly sealing body 5. The assembled sealing member 5 has an upper valve plate 13, a lower valve plate 15, and a bottom plate 16. The bottom plate 16 is formed with an internal gas discharge hole 21. At least one portion of the internal gas discharge holes 21 overlaps with the valve hole forming portion 15b of the lower valve plate 15 when viewed in the axial direction of the battery case 1. According to this structure, even if the electrode group 20 rises little by little by the increase of battery internal pressure, for example, even if the bottom plate 16 is pushed up, a valve hole does not become clogged.

Description

Cylindrical Battery {CYLINDRICAL BATTERY}

TECHNICAL FIELD The present invention relates to a cylindrical battery, and more particularly, to an improvement in a sealing structure for improving the safety of a cylindrical battery.

Cylindrical batteries generally have a bottomed cylindrical metal battery case that houses a power generating element. The opening of the battery case is sealed by a metal sealing plate or an assembly sealing body.

The assembly sealing body has a valve mechanism for ensuring the safety of the battery. When an abnormality occurs in the battery and the pressure inside the battery case rises to a predetermined value or more, the valve mechanism is operated to release gas inside the battery case. Thereby, it can prevent that a crack etc. generate | occur | produce in a battery case.

6 shows an example of a conventional cylindrical battery. The battery 100 is a lithium ion secondary battery, and the electrode group 110 in which the positive electrode 104 and the negative electrode 106 are wound in a spiral shape with the separator 108 interposed therein is housed in the battery case 102. have. The opening of the battery case 102 is sealed by the assembly sealing body 112.

As for the assembly sealing body 112, the bottom plate 115 is arrange | positioned at the lowermost part, the outer terminal board 116 is arrange | positioned at the uppermost part, and the upper valve plate 118, the lower valve plate 120, and the annular PTC between them. The thermistor plate 122 and the annular insulating member 124 are disposed. The upper valve plate 118 and the lower valve plate 120 are formed with annular breakable parts 118a and 120a so as to open the valve hole in the center when the internal pressure of the battery case 102 rises abnormally. In addition, a plurality of gas discharge holes 115a are formed near the edges of the bottom plate 115 of the assembled sealing body 112. In addition, a plurality of gas discharge holes 116a are also formed in the external terminal plate 116.

With the above configuration, when the internal pressure of the battery case 102 rises abnormally, the breakable portions 118a and 120a of the upper valve plate 118 and the lower valve plate 120 are broken to open the valve hole, and the battery case ( The gas inside the 102 is released to the outside.

However, as the multifunctionalization of electronic devices has progressed in recent years, more high-capacity batteries have been promoted, and as a result, the pressure inside the battery case when an abnormality occurs in a lithium ion secondary battery has also increased. In order to cope with this, various proposals have been made for a technique for more reliably securing a battery.

For example, Patent Document 1 proposes to set the area of the gas discharge hole provided in the sealing body to 0.15 to 1.2 cm 2 per battery capacity (Ah) in order to prevent rupture and ignition caused by a rapid increase in internal pressure of the nonaqueous electrolyte battery. .

Patent Document 1: Japanese Patent Laid-Open No. 6-187957

However, in the conventional cylindrical battery shown in FIG. 6, when the pressure inside the battery case 102 rises abnormally, for example, the electrode group 110 rises up little by little, and thus is arranged at the bottom of the assembly sealing body 112. The bottom plate 115 was pushed up and could be pressed against the lower valve plate 120. In such a case, the valve hole formed by the breakage of the breakable portions 118a and 120a of the upper valve plate 118 and the lower valve plate 120 is blocked by the bottom plate 115, and thus the battery case 102. It is also conceivable that the gas in the chamber cannot be released quickly.

The present invention has been made in view of the above problems, and an object thereof is to prevent the safety valve provided at the sealing portion of the battery case, which is opened when the internal pressure of the battery case rises abnormally, from being blocked by another member and not functioning.

The present invention provides a cylindrical battery including a power generating element, a bottomed cylindrical battery case for housing the power generating element, and an assembly sealing body for sealing an opening of the battery case.

The assembly sealing body includes a terminal plate having an external gas discharge hole and a bottom plate having an internal gas discharge hole, and at least one valve plate arranged therebetween,

The terminal plate and the bottom plate are conductive through the valve plate,

The valve plate has an easy break portion that breaks when the battery internal pressure rises to form a valve hole,

The assembly sealing body further provides a cylindrical battery further comprising a blockage preventing mechanism for preventing the valve hole from being blocked when the bottom plate is pressed against the valve plate.

The clogging prevention mechanism according to the present invention has a valve hole formed in the valve plate due to the increase in the battery internal pressure even when the battery inner pressure rises abnormally, the power generation element rises little by little, and the bottom plate of the assembled sealing body is pressed toward the valve plate. Prevent clogging by the bottom plate. As a result, when the battery internal pressure rises abnormally, the gas inside the case can be released more reliably, and the safety of the cylindrical battery can be further improved.

1 is a cross-sectional view showing a schematic configuration of a cylindrical battery according to Embodiment 1 of the present invention.
2 is a bottom view of the assembled sealing body of the cylindrical battery of Embodiment 1. FIG.
3 is a cross-sectional view of a modification of the cylindrical battery of Embodiment 1. FIG.
4 is a sectional view of another modified example of the cylindrical battery of Embodiment 1. FIG.
5 is a sectional view showing a schematic configuration of a cylindrical battery according to a second embodiment of the present invention.
6 is a sectional view showing a schematic configuration of a cylindrical battery according to a conventional example.

(Embodiment 1)

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings.

1, the schematic structure of the cylindrical battery which concerns on one Embodiment of this invention was shown by sectional drawing. The battery 10 of the illustrated example is a cylindrical lithium ion secondary battery, which is formed by winding a positive electrode 2, a negative electrode 3, and a separator 4 interposed therebetween in a spiral shape. Equipped. The electrode group 20 is housed in a bottomed cylindrical metal battery case 1 together with a nonaqueous electrolyte (not shown). The opening of the battery case 1 is sealed by the assembly sealing body 5, whereby the electrode group 20 and the nonaqueous electrolyte are sealed inside the battery case 1. Inside the battery case 1, an upper insulating plate 8A and a lower insulating plate 8B are arranged on the upper side and the lower side of the electrode group 20, respectively.

The assembly sealing body 5 is a hat-shaped terminal plate 11 made of a conductor, an annular PTC (positive temperature coefficient) thermistor plate 12, and a disk-shaped upper valve plate 13. And a lower valve plate 15, an annular assembly gasket 14 made of an insulator, and a bottom plate 16. The bottom plate 16 includes a bottom portion 17 disposed at the bottom of the assembly sealing body 5, a cylindrical portion 16a, and a connecting portion 16b connecting the bottom portion 17 and the cylindrical portion 16a. Include.

The bottom part 17 is circular, and the connection part 16b rises from the edge part. The flat part continues on the upper end of the rise part of the connection part 16b, and the cylindrical part 16a stands up from the edge part of the flat part further. The lower valve plate 15 is mounted on the flat portion of the connecting portion 16b.

The assembly gasket 14 is arranged between the periphery of the upper valve plate 13 and the periphery of the lower valve plate 15 so that the periphery of the upper valve plate 13 and the periphery of the lower valve plate 15 are provided. It prevents contact. In addition, the assembly gasket 14 is interposed between the cylindrical portion 16a of the bottom plate 16 and the edge portion of the terminal plate 11 so as not to directly contact.

A gasket 9 made of an insulator is arranged between the edge portion of the assembled sealing body 5, more specifically, the cylindrical portion 16a of the bottom plate 16 and the opening of the battery case 1. The gasket 9 seals between the assembly sealing body 5 and the battery case 1 and insulates them.

The terminal plate 11 and the PTC thermistor plate 12 are in contact with their periphery. The PTC thermistor plate 12 and the upper valve plate 13 are in contact with their periphery. The upper valve plate 13 and the lower valve plate 15 are in contact with their central portions. The center portion of the upper valve plate 13 and the center portion of the lower valve plate 15 are welded to each other. The lower valve plate 15 and the bottom plate 16 are in contact with the peripheral portion of the lower valve plate 15 and the connecting portion 16b and the cylindrical portion 16a of the bottom plate 16. With the above structure, the terminal plate 11 and the bottom plate 16 are electrically connected to each other via the contact portions at the center of the PTC thermistor plate 12, the upper valve plate 13, and the lower valve plate 15.

The bottom portion 17 is conducted through the anode 2 and the anode lead 6. As a result, the terminal plate 11 conducts with the positive electrode 2 and functions as an external terminal on the positive side of the battery 10. On the other hand, the battery case 1 is conducted through the negative electrode 3 and the negative electrode lead 7 to function as an external terminal on the negative electrode side of the battery 10.

If for some reason, excessive current flows in the battery 10, the temperature of the PTC thermistor plate 12 rises, and the electrical resistance of the PTC thermistor plate 12 increases. As a result, current is suppressed or blocked, and excessive current is prevented from flowing into the battery 10. As described later, when the battery internal pressure rises abnormally, a valve hole is formed in the center of the upper valve plate 13 and the lower valve plate 15, and the upper valve plate 13 and the lower valve plate 15 The contact of is extinguished. As a result, the conduction state between the terminal plate 11 and the bottom plate 16 is released.

The outer edge of the assembly gasket 14 protrudes further than the upper end of the cylindrical portion 16a of the bottom plate 16. In this state, the terminal plate 11, the PTC thermistor plate 12, the upper valve plate 13, the assembly gasket 14 and The lower valve plate 15 is fixed to the bottom plate 16. At this time, the edge portions of the terminal plate 11, the PTC thermistor plate 12 and the upper valve plate 13 are isolated by the gasket 14 for assembly so as not to contact the cylindrical portion 16a.

The terminal plate 11 of the assembly sealing body 5 has an external gas discharge hole 22. The bottom plate 16 of the assembly sealing body 5 also has an internal gas discharge hole 21.

The upper valve plate 13 has a circular shape, and an easy breaking portion 13a, which is an annular groove concentric with its shape, is formed in the center portion of the upper valve plate 13. The part enclosed by the break easy part 13a becomes the part (valve hole formation part) 13b which a valve hole opens by the break of the break easy part 13a.

The lower valve plate 15 is also circular, and has an easy-to-break portion 15a which is an annular groove concentric with its shape. The part enclosed by the easily broken part 15a becomes the part (valve hole formation part) 15b which a valve hole opens by the break | rupture of the easily broken part 15a.

The diameter of the breakable portion 15a of the lower valve plate 15 is slightly smaller than the diameter of the breakable portion 13a of the upper valve plate 13. As a result, the entire valve hole forming portion 15b of the lower valve plate 15 overlaps the valve hole forming portion 13b of the upper valve plate 13. As a result, when the battery internal pressure rises abnormally and the breakable portion 13a of the upper valve plate 13 and the breakable portion 15a of the lower valve plate 15 are broken, the valve hole of the lower valve plate 15 is broken. The formation part 15b can be prevented from clogging the valve hole formed in the upper valve board 13.

 Further, for the same reason, the diameter of the hole in the center of the PTC thermistor plate 12 is slightly larger than the diameter of the valve hole forming portion 13b of the upper valve plate 13, and the valve hole formation of the upper valve plate 13 is formed. The entire portion 13b overlaps the hole in the center of the PTC thermistor plate 12. In addition, the diameter of the center hole of the assembly gasket 14 is larger than the diameter of the hole of the center of the PTC thermistor plate 12, and the hole of the center of the PTC thermistor plate 12 is entirely assembled. ) Overlaps with the hole in the center.

Next, referring to FIG. 2, the bottom plate 16 will be described in more detail. 2 is a bottom view of the assembled sealing member.

As shown in the figure, a predetermined number (three in the illustrated example) of internal gas discharge holes 21 are formed in the bottom plate 16 of the assembly sealing body 5. Each of these internal gas discharge holes 21 overlaps with the valve hole forming portion 15b of the lower valve plate 15 when viewed in the axial direction of the battery case 1, and the remaining portion thereof is the lower valve plate 15. It is formed so as to overlap with the outer side part 15c of the. Each of the internal gas discharge holes 21 is an elongated hole that is curved along the easy breaking portion 15a of the lower valve plate 15.

Next, the operation of the safety mechanism of the battery 1 for reliably releasing the gas inside the battery case 1 when the battery internal pressure rises abnormally will be described.

If the battery internal pressure rises abnormally for any reason, the breakable portions 13a and 15a of the upper valve plate 13 and the lower valve plate 15 are broken, and the upper valve plate 13 and the lower valve plate 15 are broken. A valve hole not shown is opened. Accordingly, the gas inside the battery case 1 passes through the valve holes of the upper valve plate 13 and the lower valve plate 15 from the internal gas discharge hole 21 of the bottom plate 16 and the terminal plate 11. Is discharged to the outside of the battery case (1) from the external gas discharge hole (22). In this way, an accident due to an abnormal increase in battery internal pressure is prevented.

By the way, when the increase in battery internal pressure is too rapid, the electrode group 20 rises up little by little, whereby the bottom 17 may be pressed against the lower valve plate 15. In the conventional battery, when the bottom portion 17 is pressed against the lower valve plate 15, the valve hole opened in the upper valve plate 13 and the lower valve plate 15 by the bottom portion 17 is blocked. It is also conceivable that the gas inside the battery case 1 cannot be released quickly to the outside.

On the other hand, in the case of the present invention, the internal gas discharge hole 21 is seen in the bottom plate 16 in the axial direction of the battery case 1, and at least a part of the upper valve plate 13 and the lower valve plate 15 are formed. Are provided so as to overlap with the valve hole forming portions 13b and 15b. As a result, it is possible to prevent the valve holes of the upper valve plate 13 and the lower valve plate 15 from being completely blocked by the bottom 17. Thereby, the gas discharge path inside the battery case 1 can be secured. Therefore, the safety of the battery can be improved.

Here, it is preferable that the sum total of the length of the easily broken part 15a of the lower valve board 15 which overlaps with the internal gas discharge hole 21 shall be 50 to 80% of the length of the whole easily broken part 15a.

When the ratio is 50% or more, even when the bottom 17 of the bottom plate 16 is pressed against the lower valve plate 15, even if the bottom portion 17 is displaced in the surface direction of the bottom 17, it is possible to avoid clogging all the valve holes. have. On the other hand, since the said ratio is 80% or less, the intensity | strength of the bottom part 17 can be avoided.

3, the modification of the battery 1 of Embodiment 1 is shown.

In the battery 10 of FIG. 1, a predetermined number of internal gas discharge holes 21 provided in the bottom plate 16 are viewed in the axial direction of the battery case 1, and a part of each of them is the lower valve plate 15. It overlaps with the valve hole formation part 15b of this. In contrast, in the battery 10A of FIG. 3, the internal gas discharge holes 31 of a part of the predetermined number of internal gas discharge holes 31 and 32 provided in the bottom plate 16A are entirely lower valve plates ( It overlaps with the valve hole formation part 15b of 15). On the other hand, the other internal gas discharge holes 32 do not overlap with the valve hole forming portion 15b at all. As a result, when the bottom 17A of the bottom plate 16A is pressed against the lower valve plate 15, the valve hole can be prevented from being blocked by the bottom 17A.

Another modification of the battery 1 of Embodiment 1 is shown in FIG.

In the battery 10B of FIG. 4, the internal gas discharge holes 33 of a part of the predetermined number of internal gas discharge holes 33 and 34 provided in the bottom plate 16B are viewed in the axial direction of the battery case 1. At this time, only a part overlaps with the valve hole forming portion 15b of the lower valve plate 15. On the other hand, the other internal gas discharge holes 34 do not overlap with the valve hole forming portion 15b at all. Thereby, when the bottom part 17B of the bottom plate 16B is pressed by the lower valve plate 15, it can prevent that a valve hole is blocked by the bottom part 17B.

In addition, in the battery 10B of FIG. 4, the length of the breakable portion 15a overlapping the internal gas discharge hole 33 is less than 50%.

As understood from the above modifications, in the battery of Embodiment 1, at least a part of at least one of the internal gas discharge holes of the internal gas discharge holes provided in the bottom plate of the assembly sealing body is formed with the valve hole forming portion of the lower valve plate. You just need to overlap. In addition, the arrangement | positioning of a gas discharge hole and the ratio to the bottom plate (length overlapping with an easily broken part) are not fundamentally limited, either. However, the safety of the battery can be most reliably improved by providing the internal gas discharge holes in the arrangement and ratio as shown in FIG. 2.

Furthermore, there may be one internal gas exhaust hole formed in the bottom plate, or two or more.

Next, the Example of this invention concerning Embodiment 1 is demonstrated. In addition, this invention is not limited to a following example.

≪ Example 1 >

The test body which consists of lithium ion secondary batteries was manufactured as follows.

(Manufacture of Anode)

As a positive electrode active material, lithium cobalt acid (LiCoO 2) having an average particle diameter of 10 μm was used. To 100 parts by weight of a positive electrode active material, 8 parts by weight of polyvinylidene fluoride (PVDF) as a binder, 3 parts by weight of acetylene black as a conductive material, and an appropriate amount of N-methyl-2-pyrrolidone (NMP) are mixed The mixture paste was prepared.

The positive electrode mixture paste was applied to both surfaces of the positive electrode current collector made of aluminum foil except for the connecting portion of the positive electrode lead 6 and dried to form a positive electrode mixture layer. Thus, the precursor of the positive electrode was produced, and then it was rolled to obtain a positive electrode. At this time, the precursor of the positive electrode was rolled so that the thickness of the positive electrode mixture layer per side of the current collector may be 70 μm.

The aluminum foil used as the positive electrode current collector had a length of 600 mm, a width of 54 mm, and a thickness of 20 μm. In addition, the connection part of the positive electrode lead 6 was formed in the winding start part of a positive electrode as mentioned later.

(Manufacture of Cathode)

As the negative electrode active material, artificial graphite having an average particle diameter of 20 μm was used. To 100 parts by weight of the negative electrode active material, 1 part by weight of styrene butadiene rubber as a binder, 1 part by weight of carboxymethyl cellulose as a thickener, and an appropriate amount of water were mixed to prepare a negative electrode mixture paste.

The negative electrode mixture paste was applied to both surfaces of the negative electrode current collector made of copper foil except for the connection portion of the negative electrode lead 7 and dried to form a negative electrode mixture layer. In this way, the precursor of the negative electrode was produced, and then it was rolled to obtain a negative electrode. At this time, the precursor of the negative electrode was rolled so that the thickness of the negative electrode mixture layer per side of the current collector became 65 μm.

Moreover, the length of the copper foil used as a negative electrode collector was 630 mm, width was 56 mm, and thickness was 10 micrometers. In addition, the connection part of the negative electrode lead 7 was formed in the winding end part of a negative electrode.

(Manufacture of Assembly Seals)

The assembled sealing member 5 shown in FIG. 1 was manufactured. The upper valve plate 13 and the lower valve plate 15 were made of aluminum. The terminal plate 11 was made of iron. The bottom plate 16 was made of aluminum. The assembly gasket 14 was made of polypropylene. The inner gas discharge hole 21 of the bottom plate 16 has a valve hole of the lower valve plate 15 having an inner portion of a shape (hereinafter referred to as a projection shape) when viewed in the axial direction of the battery case 1. It overlapped with the part 15b, and it formed so that the outer part may overlap with the outer part rather than the easily broken part 15a of the lower valve board 15. As shown in FIG.

(Assembly of the battery)

The positive electrode and negative electrode produced as mentioned above were laminated | stacked through the separator 4 between them, and the laminated body was obtained. As the separator 4, a polyethylene porous membrane having a thickness of 20 µm was used. The positive electrode lead 6 was connected to the winding start part of the positive electrode of the obtained laminated body, and the negative electrode lead 7 was connected to the winding end part of the negative electrode. The positive electrode lead 6 and the negative electrode lead 7 were respectively connected to the said connection part by the ultrasonic welding method. In this state, the laminate was wound in a vortex form to obtain an electrode group 20.

The electrode group 20 thus obtained was accommodated in the iron battery case 1. At this time, the positive electrode lead 6 is welded to the bottom plate 16 of the assembled sealing member 5 having the polypropylene gasket 9 attached to the edge portion by a laser welding method, and the negative electrode lead 7 is battery case. The bottom part of (1) was welded by the resistance welding method. The battery case 1 used was one having a diameter (outer diameter) of 18 mm, a height of 65 mm, and a can wall thickness of 0.15 mm. The thickness of this battery case 1 is close to the thickness of the battery case of the cylindrical lithium ion secondary battery normally marketed. In addition, the upper insulating plate 8A and the lower insulating plate 8B made of polypropylene were arranged in the upper side and the lower side of the electrode group 20, respectively. In addition, a groove was formed in a position close to the bottom of the side wall of the battery case 1 to form a crack scheduled portion.

Then, the nonaqueous electrolyte was injected into the battery case 1. A nonaqueous electrolyte was prepared by dissolving lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1.0 mol / L in a mixed solvent in which ethylene carbonate and ethyl methyl carbonate were mixed in a one-to-one volume ratio.

And the protrusion part 1a (refer FIG. 1) which protrudes inward along the circumferential direction of the battery case 1 was formed at the position 5 mm from the opening edge part of the battery case 1. As a result, the electrode group 20 was held inside the battery case 1.

Next, the assembly sealing body 5 was arrange | positioned in the opening part of the battery case 1 so that it may be mounted on the protrusion part 1a. Thereafter, the opening of the battery case 1 was crimped to bend inward to seal the battery case 1.

As mentioned above, ten test bodies which consist of a cylindrical lithium ion secondary battery of 18 mm in diameter and 65 mm in height were manufactured. The design capacity of this lithium ion secondary battery was 2600 mAh.

<Example 2>

Ten test bodies which consist of lithium ion secondary batteries were produced by the method similar to Example 1 except having used the battery case 1 whose thickness of a can wall is 0.12 mm.

<Example 3>

Ten test bodies which consist of lithium ion secondary batteries were produced by the method similar to Example 1 except having used the battery case 1 whose thickness of a can wall is 0.10 mm.

Comparative Example 1

The same method as in Example 3, except that the gas discharge hole whose projection shape does not overlap at all with the valve hole forming portion 15b of the lower valve plate 15 is provided on the bottom plate of the assembled sealing member (see FIG. 6). As a result, ten test bodies made of lithium ion secondary batteries were produced.

The following tests were done about each of the ten test bodies of Examples 1-3 and the comparative example 1. First, the battery was charged at a constant current of 1500 mA under an environment of 25 ° C. until the battery voltage became 4.25 V. The test body after filling was put on the hotplate, and it heated so that temperature might rise by 1 degreeC every second to 25 degreeC-200 degreeC. And the number of the test bodies which the small crack generate | occur | produced in the battery case 1 was counted.

The above results are shown in Table 1.

 As shown in Table 1, in Examples 1-3, the crack did not generate | occur | produce in the test body. This is because in Examples 1 to 3, at least a part of the projection shape of the at least one internal gas discharge hole 21 of the bottom plate 16 overlaps the valve hole forming portion 15b of the lower valve plate 15. . As a result, even when the bottom portion 17 is pressurized by the lower valve plate 15 due to the increase in the battery internal pressure, all the valve holes opened in the lower valve plate 15 are blocked by the bottom portion 17. It seems to be because there was not. Therefore, like Example 3, even if the thickness of the battery case 1 was made considerably thinner than a normal one (see Example 1), cracking did not occur.

In contrast, in Comparative Example 1, there were three cracks in the test body. In these test bodies, when the bottom portion 17 is pressed against the lower valve plate 15 by the increase in the battery internal pressure, the valve hole opened in the lower valve plate 15 is blocked by the bottom portion 17. It is considered that it is because battery internal pressure became excessively large.

This result in the comparative example 1 is considered to originate also in making the thickness of the battery case 1 considerably thinner than usual. However, even if the thickness of the battery case 1 is a normal thickness, it is impossible to conclude that there are no batteries having the same cracks as in Comparative Example 1 among the batteries of thousands, tens of thousands, or hundreds of thousands.

Therefore, it can be said that the said result shows the improvement of the safety of a battery by this invention.

(Embodiment 2)

Next, Embodiment 2 of this invention is described. In FIG. 5, the schematic structure of the battery which concerns on Embodiment 2 is shown by sectional drawing. The second embodiment is a modification of the first embodiment, and a part different from the first embodiment will be mainly described below.

In Embodiment 2, as shown in FIG. 5, in the bottom plate 16C, the internal gas discharge hole 35 is not formed in the position which overlaps with the valve hole formation part 15b of the lower valve board 15. As shown in FIG. . Instead, the bottom plate 16C has a protrusion 23 that abuts the outer portion 15c of the lower valve plate 15 when the bottom portion 17C is pressed against the lower valve plate 15. The protruding portion 23 prevents the valve hole of the lower valve plate 15 from being blocked by the bottom portion 17C.

More specifically, in the battery 10C of FIG. 5, the protrusion 23 is provided at a position facing the outer side 15c of the lower valve plate 15 of the bottom 17C. By providing the protrusion part 23 in such a position, even if the bottom part 17C is pressed by the lower valve board 15, it becomes possible to ensure the space | gap between the bottom part 17C and the lower valve board 15. As shown in FIG. Therefore, it is possible to avoid blocking the valve hole opened in the lower valve plate 15 by the bottom portion 17C. In addition to providing the protrusion 23 on the bottom 17C, an internal gas discharge hole is formed at a position overlapping with the valve hole forming portion 15b of the lower valve plate 15 of the bottom 17C. Of course it is possible.

As shown in FIG. 5, the protruding portion 23 may be formed of a member different from the bottom portion 17C. Moreover, the protrusion part 23 can also be formed integrally with 16 C of bottom plates. The material should just have rigidity to some extent, and is not specifically limited. The shape may be annular or may be an independent projection. In order to more reliably prevent the valve hole of the lower valve board 15 from being blocked by the bottom part 17C, it is preferable to set it as at least 3 or more in the case of independent protrusion type.

As described above, the lower valve plate 15 is provided by providing the protrusion 23 at a position where the bottom portion 17C is in contact with the outer portion 15c of the lower valve plate 15 when the bottom portion 17C is pressed toward the lower valve plate 15. Can be prevented from being blocked by the bottom portion 17C. Thus, the safety of the cylindrical battery is improved.

According to the present invention, it is possible to provide a cylindrical battery with improved safety. Such a cylindrical battery of the present invention is particularly useful as a power source for portable electronic devices such as personal computers, mobile phones, mobile devices, portable digital assistants (PDAs), portable game devices, and video cameras. In addition, in transportation equipment such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle, it is also useful as a power source for assisting the driving of the electric motor. It is also useful as a power source for driving power tools, vacuum cleaners and robots, and also as a power source for plug-in HEVs.

One… Battery case,
5... Assembly ball body,
10, 10A, 10B, 10C... battery,
11 ... Terminal Block,
13... Upper valve plate,
13a... Ease of Breaking,
13b... Valve hole forming part,
15... Lower valve plate,
15a... Ease of Breaking,
15b... Valve hole forming part,
15c... Outer,
16, 16A, 16B, 16C... Bottom Plate,
17, 17A, 17B, 17C... Bottom View,
20... Electrode group,
21, 31, 32, 33, 34, 35... Internal gas exhaust holes,
22... External gas exhaust holes,
23 ... projection part,

Claims (10)

A cylindrical battery comprising a power generation element, a bottomed cylindrical battery case accommodating the power generation element, and an assembly sealing body sealing the opening of the battery case.
The assembly sealing body comprises a terminal plate having an external gas discharge hole and a bottom plate having an internal gas discharge hole and at least one valve plate arranged therebetween,
The terminal plate and the bottom plate are conducted through the valve plate,
The valve plate has an easy break portion that breaks when the battery internal pressure rises to form a valve hole,
And the assembly sealing body further comprises a blockage preventing mechanism for preventing the valve hole from being blocked when the bottom plate is pressed against the valve plate. The said clogging prevention mechanism consists of the said internal gas discharge | emission hole and the said valve plate, When looking at the axial direction of the said battery case, at least one part of the said internal gas discharge | emission hole is the said valve hole of the said valve plate. Cylindrical battery that overlaps the opening. 3. The portion of claim 2, wherein the bottom plate has a plurality of the internal gas discharge holes, and when viewed in the axial direction of the battery case, only a part of each of the internal gas discharge holes opens the valve hole of the valve plate. And overlapping cylindrical battery. The method according to claim 2, wherein the bottom plate is made of a first disc-shaped member,
The valve plate is made of a second disc-like member arranged concentrically with the bottom plate,
The part in which the said valve hole of the said valve board is opened consists of a circular part concentric with the said valve board, being located in the center part of the said valve board,
A cylindrical battery in which the breakable portion is annular and 50 to 80% of its total length overlaps the internal gas discharge hole. The method of claim 2, wherein the bottom plate has a plurality of the internal gas discharge holes,
When viewed in the axial direction of the battery case, at least one of the internal gas discharge holes overlaps with a portion where the valve hole of the valve plate is opened, and the other gas discharge hole is the valve hole of the valve plate. A cylindrical cell that does not overlap at all with this opening. The method of claim 2, wherein the bottom plate has a plurality of the internal gas discharge hole,
When viewed in the axial direction of the battery case, at least one of the internal gas discharge holes overlaps with a portion where the valve hole of the valve plate is opened, and another internal gas discharge hole is the valve of the valve plate. Cylindrical cells that do not overlap at all with openings. The projection block provided in the bottom plate so that the said blockage prevention mechanism protrudes toward the said valve plate, The position of the said projection part becomes the said valve hole of the said valve plate, when it sees from the axial direction of the said battery case. A cylindrical battery that overlaps with parts other than the opening. The said power generating element is comprised from the positive electrode which can occlude and discharge lithium ion, the negative electrode which can occlude and discharge lithium ion, the separator interposed between the said positive electrode and negative electrode, and the nonaqueous electrolyte which has lithium ion conductivity. Cylindrical battery. The cylindrical battery according to claim 1, wherein the positive electrode comprises a current collector made of a positive electrode active material and a metal foil, and the positive electrode active material contains a transition metal oxide containing lithium. The cylindrical battery according to claim 1, wherein the negative electrode includes a negative electrode active material and a current collector made of metal foil, and the negative electrode active material contains a carbonaceous material.

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